This invention relates to a bearing lubricating system for a vertical shaft electric rotary machine in which centrifugal pump means is disposed around a vertical shaft thereof to pump a lubricating oil adjacent to associated bearing unit to an external oil cooler and return the lubricating oil cooled by the oil cooler back to the bearing unit, thereby to lubricate the bearing unit.
A vertical shaft electric rotary machine of the known type has comprised a pair of upper and lower shafts extending in vertically aligned relationship and in the opposite directions from a rotor, an upper guide bearing disposed in an upper oil tank fitted into an upper bracket to rotatably support the upper shaft, and a frange unit integral with the lower shaft to include a pendent cylindrical portion coaxial with the lower shaft. Then a lower guide bearing radially supports the periphery of the frange unit and a thrust bearing support the lower end of the cylindrical portion to rotatably support a frange unit and the lower shaft. The two bearing are disposed in, a lower oil tank subsequently located within a lower bracket.
A conventional bearing lubricating system of the type referred to has comprised an amount of a lubricating oil charged in each of the upper and lower oil tanks, and centrifugal pump means including a plurality of force delivery holes radially extending through the pendent cylindrical portion of the frange unit and an enclosure for enclosing the outlet side of the force delivery holes with an annular gap formed between the bottom thereof and an adjacent part of the pendent cylindrical portion to permit the passage of the lubricating oil therethrough. The centrifugal pump means is operated to pump the lubricating oil having lubricated the bearings to increase in temperature to an external oil cooler where the oil is cooled by a cooling coil having cooling water flowing therethrough. The cooled lubricating oil is returned back to the lower tank to again lubricate the bearings after which the process as described above is repeated.
On the other hand, the lubricating oil within the upper oil tank lubricates the upper guide bearing to increase in temperature. The lubricating oil increased in temperature is cooled by an oil cooler in the form of a cooling coil disposed within the upper oil tank through which cooling water is flowing.
In conventional bearing lubricating systems such as described above, the upper oil tank has been large-scaled because of the presence of the oil cooler and also it has been required to flow the oil cooler with cooling water through a piping therefor. The use of such a piping has made the maintenance of the conventional systems troublesome. For example, it has been required to always take precaution against any leakage of water through the connection of the oil cooler to the piping.
Accordingly it is an object of the present invention to provide a new and improved bearing lubricating system for a vertical shaft electric rotary machine simplified in construction and eliminating the maintenance concerning leakages of water.